[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SELECT GET_LOCK("d3dd46b14b9fb42e351e8ef12feaa274", 60)
LIMIT 0, 1

/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string, NULL, NULL)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/lib/db/connection.php:330
#1: Bitrix\Main\DB\Connection->query(string, NULL, integer, integer)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/lib/db/connection.php:358
#2: Bitrix\Main\DB\Connection->queryScalar(string)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/security/lib/session.php:114
#3: Bitrix\Security\SessionTable::lock(string, integer)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/security/classes/general/session_db.php:52
#4: CSecuritySessionDB::read(string)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/security/classes/general/session_handler.php:23
#5: CSecuritySessionHandler->read(string)
	
#6: session_start()
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/lib/session/session.php:130
#7: Bitrix\Main\Session\Session->start()
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/lib/session/kernelsessionproxy.php:52
#8: Bitrix\Main\Session\KernelSessionProxy->start()
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/include.php:299
#9: require_once(string)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/include/prolog_before.php:14
#10: require_once(string)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/include/prolog.php:10
#11: require_once(string)
	/home/bitrix/ext_www/bookling.ua/bitrix/header.php:1
#12: require(string)
	/home/bitrix/ext_www/bookling.ua/catalog/index.php:1
#13: include_once(string)
	/home/bitrix/ext_www/bookling.ua/bitrix/modules/main/include/urlrewrite.php:159
#14: include_once(string)
	/home/bitrix/ext_www/bookling.ua/bitrix/urlrewrite.php:2